Hazards in the home from mains electricity

Hazards can include:

1. Long cables or frayed cables.2. Cables in contact with something hot or wet.3. Pet rabbits or children (always hazardous).4. Water near sockets or shoving things into sockets.5. Damaged plugs, or too many plugs in one socket.6. Lighting sockets without bulbs in.7. Appliances without their covers on.

Plugs and cables - Learn the safety features.

Get the wiring right:

1. The right coloured wire is connected to each pin.2. No bare wires showing inside the plug.

3. Cable grip tightly fastened over the cable outer layer.

Plug features:

1. The metal parts are made of copper or brass because these are very good conductors.2. The case, cable grip and cable insulation are all made of plastic because this is a really good insulator and is flexible too.3. This all keeps the electricity flowing where it should.

Earthing and Fuses Prevent Fires and Shocks

The live wire alternates between a high +ve and -ve voltage, with an average of about 230V. The neutral wire is always at 0V. Electricity normally flows in and out through the live and neutral wires only. The earth wire

and fuse (or circuit breaker) are just for safety and work together like this:

If a fault develops in which the live somehow touches the metal case, then because the case is earthed, a big current flows in through the live, through the case and out down the earth wire.

This surge in current blows the fuse (or trips the circuit breaker), which cuts off the live supply.

This isolates the whole appliance making it impossible to get an electric shock from the case. It also prevents the risk of fire caused by the heating effect of a large current.Fuses should be rated as near as possible but just higher than the normal operating current.

All Appliances must be Earthed

All appliances with metal cases must be "earthed" to avoid the danger of electric shock.

"Earthing" just means the metal case must be attached to the earth wire in the cable.If the appliance has a plastic casing and no metal parts showing then it's said to be double insulated.Anything with double insulation like that doesn't need an earth wire, just a live and neutral

We're talking 230 volts — worth being carefulThis stuff's a bit complicated, it’s true. But you have to learn it all the same-Learn all four steps and check you know them by drawing the diagram and annotating it.

The National Grid supplies the Whole Country with Electricity

1. National Grid is the network of pylons and cables which covers the whole country.

2. It takes electricity from the power stations, to just where it's needed in homes and industry.

3. It enables power to be generated anywhere on the grid; and to then be supplied anywhere else on the grid.

GCSE level revision questions.

STEP 2

1. Which of the following are hazards in the home from mains electricity:

Long trailing cables.

A correctly wired plug.

Pets and children.

Water near sockets.

Bulbs in all lighting sockets.

Covers on all appliances.

Finished

2. The right colour wire should be connected to each:

plug pin Plate

Finished

3. Which are good conductors?

Plastic Copper Brass

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Step 5/6 questions

4. Please type a one or two word/numerical answer to the following questions:

a. What is the colour of a neutral wire in a plug?b. What is the colour of a live wire in a plug?c. What are the two colours of an earth wire in a

plug?d. What is the average voltage of a live wire?e. What is the average voltage of a neutral wire?f. What wire can we leave out of a double insulated

plug?

STEP 9 questions

5. Give an example of one home hazard.6. Give one example of what can make a cable hazardous.

STEP 10 Questions

7. In a short sentence describe the role of the earth wire and the fuse in a plug.

8. In a short sentence explain why appliances with metal cases should be earthed.

9. In a short sentence describe what double insulation means.

Step 11 question

10. In a short paragraph describe the National Grid and why we need it.